In 1893, a desperately poor cleaner named Mary becomes witness to a murder. Archie, one of the first artists to work for the police, draws the man she says she saw at the scene. Fascinated by Mary's own features, Archie persuades her to sit for a portrait, but the man who buys the picture really wants to buy Mary. When he realizes he's betrayed her, Archie takes Mary to hide with his friends without realizing the gravity of the link she provides between his wealthiest clients, the poorest slums, terrible secrets, and a violent thug now looking for the very man Mary described to the police. As this gripping thriller uncoils, it paints an intricate, vibrant picture of the layers of Victorian London, where the poor are commodities, criminals have nothing to lose, and the rich can buy anything.